This invention relates to an assembly for attaching thermoplastic fasteners to a workpiece using a technique known as spin welding or friction welding. In particular, this invention relates to a two component fastening assembly in which one component is a base member which is spin welded to a substrate and the other component is a standoff member which is rotatably adjustable.
In a two component fastening assembly where one component is a spin welded base member and the other component is a standoff member for mounting a quarter-turn fastener, there is oftern encountered the difficulty of accommodating the need for the quarter-turn fastener to be installed into a workpiece opening at an angle relative to the spin welded base member. This invention overcomes the angular alignment problem by providing a means for angularly setting the quarter-turn fastener relative to the base member.
There is the additional problem in maintaining the angular setting of the base member during the installation of the quarter turn fastener. This invention overcomes this problem by the use of a ratchet connecting means that permits the angular setting of the base member to be made in only one rotational direction which is opposite to the rotational force exerted by the quarter turn fastener as it is installed.
These and other objects of the invention are achieved with a two component fastening assembly which combines a spin welded base member and a rotatable standoff member. The spin welding assembly of this invention utilizes a circular base member formed of thermoplastic material to provide the means for attaching by frictional spinning to a substrate. A standoff member having a circular flange portion of a diameter slightly larger than the diameter of the base member is rotationally mounted by a snap fitting connection onto the base member. The snap fitting connection includes a ratchet means for connecting the flange portion onto the base member in a manner to permit the standoff member to be rotated in one direction only. The standoff member has a mounting plate portion transversely extending to the base member with a centrally located mounting aperture of a configuration designed to receive the head of a quarter turn fastener. The head of the quarter turn fastener is installed into the mounting aperture of the standoff member with a rotative action to firmly capture the head portion. The direction of the rotative action for the quarter turn fastener is opposite to the direction of rotation permitted by the ratchet means to prevent any angular misalignment of the quarter-turn fastener relative to the base member.